The invention relates to semiconductor device packaging and, more particularly, to techniques for surface mount technology (SMT) for mounting SMT components to substrates, and providing an improved solder joint.
With the trend for higher wiring density and improved electrical performance in flip chip plastic ball grid array (FCPBGA) laminate chip carriers, it is desirable to place passive components, such as capacitors, on the chip carriers as close to the chip as possible. Recent developments in capacitor technology have resulted in small multi-terminal ceramic capacitors. These capacitors are typically soldered directly onto copper (Cu) pads on the FCPBGA laminates. Typical multi-terminal capacitors have 6-10 terminals, requiring a like number of solder joints, per capacitor. The capacitor may be on the top or the bottom of the laminate chip carrier. (The “laminate” chip carrier may also be referred to as an “organic” substrate.)
Surface Mount Technology (SMT) is a technique for populating hybrids, multichip modules, and circuit boards, in which packaged components are mounted directly onto the surface of the substrate. A layer of solder paste is screen printed onto the pads and the components are attached by pushing their leads into the paste. When all of the components have been attached, the solder paste is melted using either reflow soldering or vapor-phase soldering.
A surface mount device (SMD) or component is an electronic component, ranging from discrete passive components, such as chip resistors and chip capacitors, to VLSI (very large scale integration) chips, attached to the surface of a substrate such as a printed circuit board or a ball grid array (BGA) package substrate, either directly or through a surface-mount connector, rather than by means of wires, leads or holes in the board.
Flip Chip technology is a type of SMT, and refers to situations where a device—typically a device having solder bumps—is mounted face-down (active side down) onto a substrate.